{}

Our Brands

Impact-Company-Logo-English Black-01-177x54

Schneider Electric Gulf Countries and Pakistan Website

Welcome to our website.
Search FAQs
What is the definition of ANSI 81R - Rate of change of frequency?
Protection function used for fast disconnection of a generator or load shedding
control. Based on the calculation of the frequency variation, it is insensitive to
transient voltage disturbances and therefore more stable than a phase-shift
protection function.

Disconnection
In installations with autonomous production means connected to a utility, the “rate of
change of frequency” protection function is used to detect loss of the main system in
view of opening the incoming circuit breaker to:
  • protect the generators from a reconnection without checking synchronization
  • avoid supplying loads outside the installation.
Load shedding
The “rate of change of frequency” protection function is used for load shedding in
combination with the underfrequency protection to:
  • either accelerate shedding in the event of a large overload
  • or inhibit shedding following a sudden drop in frequency due to a problem that should not be solved by shedding.

Schneider Electric United Arab Emirates

Explore more
Range:
Articles that might be helpful Users group

Discuss this topic with experts

Visit our Community for first-hand insights from experts and peers on this topic and more.
Explore more
Range: